<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      * {
        margin: 0;
        padding: 0;
      }
      header {
        position: fixed;
        left: 0;
        top: 0;
        height: 60px;
        width: 100%;
        background-color:#9df3f3;
    
        text-align: center;
        line-height: 60px;
      }

      .main {
        text-align: center;
        line-height: 60px;
        height: calc(100vh - 120px);
        padding: 60px 0;
        /* background:-webkit-linear-gradient(top,blue,red); */
        position: relative;
      }

      .main .yuan1 {
        position: absolute;
        left: 50%;
        top: 50%;
        margin-top: -75px;
        margin-left: -75px;
        width: 150px;
        height: 150px;
        background-color: teal;
        border-radius: 50%;
        
        display: flex;
        justify-content: center;
        align-items: center;
        font-size: 20px;
        color: #ffffff;
        font-weight: bolder;

        animation: yuan1 10s infinite;
      }

      .main .yuan2 {
        position: absolute;
        left: 50%;
        top: 50%;
        transform: translate(-50%, -50%);
        width: 150px;
        height: 150px;
        background-color: rgb(132, 206, 206);
        border-radius: 50%;
        animation: yuan2 2s infinite;
      }

      .main .yuan3 {
        position: absolute;
        left: 50%;
        top: 50%;
        transform: translate(-50%, -50%);
        width: 150px;
        height: 150px;
        background-color: rgb(134, 212, 212);
        border-radius: 50%;
        animation: yuan3 2s 0.5s infinite;
      }

      @keyframes yuan1 {
        0% {
          transform: rotate(0deg);
        }
        100% {
          transform: rotate(360deg);

        }
      }
      @keyframes yuan2 {
        0% {
          opacity: 1;
        }
        100% {
          width: 250px;
          height: 250px;
          opacity: 0;
        }
      }
      @keyframes yuan3 {
        0% {
          opacity: 1;
        }
        100% {
          width: 300px;
          height: 300px;
          opacity: 0;
        }
      }

      footer {
        position: fixed;
        left: 0;
        bottom: 0;
        height: 60px;
        width: 100%;
        background-color: #0e5c5c;
        color: #ffffff;
        text-align: center;
        line-height: 60px;
      }
    </style>
  </head>
  <body>
    <header>标题栏</header>
    <div class="main">
      <p>内容</p>
      
      <div class="yuan3"></div>
      <div class="yuan2"></div>
      <div class="yuan1">CLICK</div>
    </div>
    <footer>底栏</footer>

    <script src="./assets/jquery.js"></script>
    <script>
     
    </script>
  </body>
</html>
